The mean minimum temperature is 13*C to 17*C in December and January, but it rises to 26*C to 29* C in May. The minimum temperature falls rapidly after October, and less than 10oC was recorded on individual days.

The mean diurnal variation is 12*C for the year as a whole. It is 13*Cto 15*C in February and March, and 8*C in the monsoon months of July and August.

The climate is pleasant from November to February. The summer months of April and May are uncomfortable due to oppressive heat. The period from July to September is warm, humid and uncomfortable

Rainfall
More than 75 per cent of the rainfall is received during the south-west monsoon season, i.e., from June to September, July being the month when it rains. September is the month, when there are rains. The south-west monsoon sets in by the 7th of June. Its advent is sudden and the rainfall increases from less than 5 per cent (of the annual) in May to 15 per cent in June.

Excessive Rainfall
In the case of Hyderabad, out of 6 years of excessive rain, as many as four years (1903, 1915, 1916 and 1933) were with rainfall of more than 150 per cent. Generally speaking, 1903 was a year of more than 150 per cent of rainfall.

Humidity
Humidity in the morning is very high exceeding 80 per cent from July to September. In the dry months of March, April and May, humidity is generally low with an average of 25 to 30 per cent and decreases to 20 per cent at individual stations.

Cloudiness
June to October is the period when more than half of the sky is covered with clouds, while only about 2/8 of the sky is clouded from January to March. Half of the days in July and August have overcast skies. About 10 to 13 days in the months of January, February and March, the skies are free from clouds in clear weather.